Stereoselective synthesis of (22Z)-25-hydroxyvitamin D2 and (22Z)-1α,25-dihydroxyvitamin D2

The Centennial Collection of VDR Ligands: Metabolites, Analogs, Hybrids and Non-Secosteroidal Ligands

Since the discovery of vitamin D a century ago, a great number of metabolites, analogs, hybrids and nonsteroidal VDR ligands have been developed. An enormous effort has been made to synthesize compounds which present beneficial properties while attaining lower calcium serum levels than calcitriol. This structural review covers VDR ligands published to date.

Crystal structure of (1R,3aR,7aR)-1-{(S)-1-[(2R,5S)-5-(3-hy-droxy-pentan-3-yl)tetra-hydro-furan-2-yl]eth-yl}-7a-methyl-2,3,3a,4,5,6,7,7a-octa-hydro-1H-inden-4-one

The title compound, C21H36O3, contains an oxolane ring, and six defined stereocentres and may serve as a useful synthon for the synthesis of calcitriol analogues. The configurations of the chiral C atoms of the side chain were unambiguously established in the refinement. In the crystal, C-H⋯O and extremely weak O-H⋯O hydrogen bonds arising from the sterically hindered alcohol group link the mol-ecules into a three-dimensional network.